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Hubble Captures Comet ISON |
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Comet ISON is potentially the "comet of the century" because around the time the comet makes its closest approach to the Sun, on November 28, it may briefly become brighter than the full Moon. Right now the comet is far below naked-eye visibility, and so Hubble was used to snap the view of the approaching comet, which is presently hurtling toward the Sun at approximately 47,000 miles per hour. When the Hubble picture was taken on April 10, the comet was slightly closer than Jupiter's orbit at a distance of 386 million miles from the Sun. Even at that great distance the Sun is warming the comet enough to trigger outgassing from its frozen gases locked up in the solid nucleus. Hubble photographed a jet blasting dust particles off the sunward-facing side of the comet's nucleus. Preliminary measurements from the Hubble images suggest that the nucleus of ISON is no larger than three or four miles across. The comet was discovered in September 2012 by the Russian-led International Scientific Optical Network (ISON) using a 16-inch telescope. |
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The Hubble Legacy Archive (HLA) announces the availability of Data
Release 5 as of March 8, 2011. New in this release are a new,
interactive footprint interface (pictured); multi-wavelength source
lists; high-level WFC3 science products from the Early-Release Science
and the Multi-Cycle Treasury program CANDELS; and the ability to
obtain source information directly from the Interactive Display
overlay. DR5 also completes the processing of the WFPC2 data, all of
which are now public.
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A general theme to the top recommendations of the Astro2010 Decadal Survey
is the importance of wide-area surveys. These surveys will provide data that
are much deeper and covering larger solid angles than previous surveys, opening
new parameter space for discovery.
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